Sunspots – UPSC Prelims

  • Sunspots: These are areas that appear dark on the surface of the Sun because they are cooler than other parts of the Sun’s surface.
  • Why are sunspots relatively cool? It’s because they form in areas where magnetic fields are particularly strong. These magnetic fields are so strong that they keep some of the heat within the Sun from reaching the surface.
  • What are Solar Flares and Coronal Mass Ejection (CME)?
    • The magnetic field lines near sunspots often tangle, cross, and reorganize. This can cause a sudden explosion of energy called a solar flare.
    • Sometimes solar flares also cause hot plasma to be ejected from the Sun, causing a solar storm, and this is called Coronal Mass Ejection (CME). Coronal Mass Ejections can harbour energies exceeding that of a billion atomic bombs.

What are the effects of Solar Activity on Earth?
  • Auroras: When charged particles from a CME reach areas near Earth, they can trigger intense lights in the sky, called auroras.
  • Affects Electronics and Satellites: The energy, radiation and high-energy particles emitted by the flares can affect Earth-bound objects and life on Earth – it can affect the electronics within satellites and affect astronauts.
  • Failure of Power Grids: Very powerful Earth-directed coronal mass ejections can cause the failure of power grids and affect oil pipelines and deep-sea cables.
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